THE STIMULATING EFFECTS OF ADRENALINE AND ANTERIOR PITUITARY HORMONES ON THE RELEASE OF FREE FATTY ACIDS FROM ADIPOSE TISSUE

Abstract

SUMMARY: The quantity of free fatty acids (FFA) released from rat epididymal fat pads in vitro and their concentration within the tissue were determined. The addition of adrenaline, adrenocorticotrophic hormone (ACTH), thyroid stimulating hormone (TSH) and growth hormone (GH) each increased the release of FFA, and their respective minimum effective concentrations were 0·125, 0·004, 0·5 and 1·25 μg./ml. of medium. In every case, the increased release of FFA was associated with a rise in the quantity present within the pads, and the amount released closely paralleled their concentration within the tissue. It is suggested that the stimulatory effect of all four hormones on the release of FFA from adipose tissue is largely a manifestation of their activity of increasing the concentration of FFA within the cells, and this they do by facilitating the net conversion of storage triglyceride to fatty acid. The significance of the relative activities of the hormones in vitro is discussed and compared with their fatty acid mobilizing effects in vivo.